All you have to do is bring up the timeline, click on the 'make animation' icon, and select which framerate you want before you hit start render. There's no effect on the PZ3 file or the Vue scene file until you start a render, so -none- of the render settings are locked. There may be a global setting, but I usually play about with framerate in tests, so I haven't really bothered to find out if it exists. And 15 fps =might= be acceptable for a very low res render for use as a gif on a webpage, but you -will- see flicker. 24 fps is acceptable -if you have some form of motion blur enabled- ; otherwise, there may also be some strobing on computer monitors. It's less likely with a TV, as the phosphors on the screen have a longer decay rate than a computer CRT.